I can not speak for the use of Avon tires on Indian bikes,but I used em on my Triumph and they did NOT last very long at all.[poor mileage]The handling was ok,but that's where it stopped.Would I use em again?? NOOOOOOOOOOOO!! But that's just my opinion FWIW.
Not on a Chieftan but on another cruiser that weighs 732 lbs and is ridden hard. Avon Cobras. Far better than the Metzelers or the Dunlops before that I had fitted, and they cope extremely well with everything the British weather can throw at them. Then again they should as they are the only motorcycle tire company making and developing tires on our island.
Have just bought a set of Avon Spirit STs for my Indian which are getting nailed on tomorrow and they do have great reviews over here. Depends what exactly you are after? If you want longevity it normally costs you in the handling stakes or the other way round as above!
I put the original Avon Cobra tires on a 2007 Yamaha Roadliner and the handling as well as the grip was way better than the OEM Bridgestones. The trade-off was tire wear with the front lasting about 8000 and the rear maybe 6500 miles. All of my subsequent bikes got Michelin Commander II tires as replacements. I got much better tread wear mileage and still had excellent handling and grip to the road even in rain.
I also used the Avon Venom X and the Cobras. I used to get about 20k on the front of my Gilroy Chief and 9-10K on the rear (2 up mostly). They sure handled our drawl bridges down here very well and I never had any problems with them. However, I sure like the 20K + that I'm getting on these dunlaps.